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Commit 56d9ead

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committed
提交234,617,101题
1 parent 4a655d2 commit 56d9ead

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4 files changed

+140
-0
lines changed

4 files changed

+140
-0
lines changed
Lines changed: 67 additions & 0 deletions
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package com.mistray.link;
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import java.util.ArrayList;
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/**
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* @author ZJY(MistRay)
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* @Project algorithm-study
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* @Package com.mistray.link
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* @create 2020年03月04日 15:02
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* @Desc
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*/
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public class PalindromeLinkedList234 {
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public static void main(String[] args) {
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System.out.println(2%2);
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}
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// 双指针法
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public boolean isPalindrome(ListNode head) {
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if (head == null || head.next == null){
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return true;
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}
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ArrayList<ListNode> list = new ArrayList<>();
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ListNode fast = head;
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ListNode slow = head;
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int count = 1;
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while (fast != null && fast.next != null) {
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list.add(slow);
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slow = slow.next;
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fast = fast.next.next;
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if (fast != null) {
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count = count + 2;
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} else {
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count++;
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}
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}
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ListNode tmp;
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if (count % 2 == 0) {
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tmp = slow;
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} else {
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tmp = slow.next.next;
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}
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for (int i = list.size() - 1; i > -1; i--) {
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if (tmp.val != list.get(i).val) {
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return false;
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}
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tmp = tmp.next;
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}
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return true;
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}
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// 复制数组双指针法
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public boolean isPalindrome2(ListNode head) {
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ArrayList<ListNode> list = new ArrayList<>();
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while (head != null) {
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list.add(head);
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head = head.next;
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}
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for (int i = 0, f = list.size() - 1; i < list.size() / 2; i++, f--) {
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if (list.get(i).val != list.get(f).val) {
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return false;
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}
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}
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return true;
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}
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}
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package com.mistray.tree;
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/**
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* @author ZJY(MistRay)
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* @Project algorithm-study
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* @Package com.mistray.tree
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* @create 2020年03月04日 9:59
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* @Desc
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*/
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public class MergeTwoBinaryTrees617 {
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public static void main(String[] args) {
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}
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public TreeNode mergeTrees(TreeNode t1, TreeNode t2) {
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if (t1 == null && t2 == null) {
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return null;
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} else if (t1 == null) {
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return t2;
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} else if (t2 == null) {
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return t1;
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} else {
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t1.val = t1.val + t2.val;
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t1.left = mergeTrees(t1.left, t2.left);
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t1.right = mergeTrees(t1.right, t2.right);
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return t1;
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}
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}
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}
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Lines changed: 29 additions & 0 deletions
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package com.mistray.tree;
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/**
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* @author ZJY(MistRay)
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* @Project algorithm-study
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* @Package com.mistray.tree
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* @create 2020年03月04日 13:31
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* @Desc
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*/
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public class SymmetricTree101 {
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public static void main(String[] args) {
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}
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public boolean isSymmetric(TreeNode root) {
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return helper(root,root);
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}
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public boolean helper(TreeNode t1, TreeNode t2) {
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if ((t2 != null && t1 != null) && t1.val == t2.val) {
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return helper(t1.right, t2.left) && helper(t1.left, t2.right);
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} else if (t1 == null && t2 == null) {
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return true;
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} else {
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return false;
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}
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}
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}
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package com.mistray.tree;
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public class TreeNode {
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int val;
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TreeNode left;
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TreeNode right;
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TreeNode(int x) {
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val = x;
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}
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}

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